Minimal translation surfaces in the Heisenberg group Nil3

A translation surface in the Heisenberg group Nil₃ is a surface constructed by multiplying (using the group operation) two curves. We completely classify minimal translation surfaces in the Heisenberg group Nil₃.     

Magnetic curves in Sasakian manifolds

In this paper we classify the magnetic trajectories corresponding to contact magnetic fields in Sasakian manifolds of arbitrary dimension. Moreover, when the ambient is a Sasakian space form, we prove that the codimension of the curve may be reduced to 2. This means that the magnetic curve lies on a 3-dimensional Sasakian space form, embedded as a totally geodesic submanifold of the Sasakian space form of dimension (2n+1).     

Mapping Receptor Density on Live Cells by Using Fluorescence Correlation Spectroscopy

Sensitive surveying : Fluorescence correlation spectroscopy (FCS) was used to study receptor density and to monitor ligand–receptor interactions on live cell membranes by the introduction of fluorescently marked aptamers, which specifically bind to certain cell‐surface receptors (see schematic representation; FITC: fluorescein isothiocyanate).

     

Switching the Solubility of PMMA Bearing Attached Cyclodextrin‐Moieties by Supramolecular Interactions with Ionic Liquids

Methacrylate‐modified β‐cyclodextrin (β‐CD) and methyl methacrylate (MMA) have been radically copolymerized to obtain hydrophobic CD copolymers. The water‐insoluble copolymers are able to form highly stable inclusion complexes with anions of ionic liquids. Surprisingly, the inclusion of the anions in the CD cavity results in a significant change of thermal and solution properties. Furthermore, it can be shown that the structure of the ionic liquid anions influences the coil structure of the copolymers. The obtained results could be proven by means of microcalorimetry, differential scanning calorimetry, and dynamic light scattering.

     

On the free vibrations of a piezoceramic hollow sphere

The aim of the paper is to analyze the free vibrations of a piezoceramic hollow sphere with radial polarization. Using the cnoidal method and a genetic algorithm solves the equations of a radially inhomogeneous spherically isotropic piezoelastic medium. The Reddy and the cosine laws represent the functionally graded property of material. It is seen that for a piezoceramic hollow sphere, the piezoelectric effect consists in increasing the values for the natural frequencies in the specified classes of vibrations.     

Chemical Profile,Cytotoxic Activity and Oxidative Stress Reduction of Different Syringa vulgaris L. Extracts

Syringa vulgaris L. (common lilac) is one of the most popular ornamental species, but also a promising not comprehensively studied source of bioactive compounds with important therapeutic potential. Our study was designed to characterize the chemical composition and to assess the antioxidant and cytotoxic properties of ethanolic extracts obtained from S. vulgaris L. flowers, leaves, bark, and fruit. The chemical profile of the ethanolic extracts was investigated using chromatographic (HPLC-DAD-ESI⁺, GC-MS) and spectral (UV-Vis, FT-IR) methods, while the protective effect against free radicals was evaluated in vitro by different chemical assays (DPPH, FRAP, CUPRAC). The cytotoxic activity was tested on two tumoral cell lines, HeLa, B16F10, using the MTT assay. Significant amounts of free or glycosylated chemical components belonging to various therapeutically important structural classes, such as phenyl-propanoids (syringin, acteoside, echinacoside), flavonoids (quercetin, kaempferol derivatives) and secoiridoids (secologanoside, oleuropein, 10-hydroxy oleuropein, demethyloleuropein, syringalactone A, nuzhenide, lingstroside) were obtained for the flowers, leaves and bark extracts, respectively. Furthermore, MTT tests pointed out a significant cytotoxic potential expressed in a non-dose-dependent manner toward the tumoral lines. The performed methods underlined that S. vulgaris extracts, in particular belonging to flowers and leaves, represent valuable sources of compounds with antioxidant and antitumoral potential.     

Temperature-programmed reduction of lightly yttrium-doped Au/CeO<Subscript>2</Subscript> catalysts

The reducibility of Au catalysts on CeO₂ supports doped with 1 and 2.5 mass% Y₂O₃ by two types of preparation methods (impregnation and co-precipitation) has been studied by temperature-programmed reduction and compared with that of pure Au/CeO₂. The kinetic parameters of reduction were determined simulating each reduction process. The capacities of these catalysts to retain oxygen have been evaluated by temperature-programmed desorption. The catalytic activities in water gas shift reaction were determined measuring CO conversion between 413 and 623 K. The catalytic performances of all these catalysts were explained in terms of mobility of the oxygen ions of the CeO₂ lattice.     

Recovering a Constant in the Two-Dimensional Navier–Stokes System with No Initial Condition

We deal with the \(2D\) -Navier–Stokes system endowed with Cauchy boundary conditions, but with no initial condition. We assume that the right-hand side is of the form \(\beta f_0+f_1\) , where \(\beta \in \mathbb {R}\) is an unknown constant. To determine \(\beta \) we are given a functional involving the velocity field \(y\) . First we prove uniqueness for the pair \((y,\beta )\) , via suitable weak Carleman estimates, and then we show the locally Lipschitz-continuous dependence of \((y,\beta )\) on the data.